The present invention relates to a cooling section for a flat rolled material,                where the cooling section has a structural frame in which a plurality of transport rollers is arranged, one behind another in a direction of transport for the flat rolled material,        where transport rollers which are immediate neighbors when looking in the direction of transport have in each case a gap between them,        where the transport rollers are each mounted in the structural frame so that each roller can rotate about a roller axis,        where the roller axes are aligned orthogonally to the direction of transport and extend horizontally, so that the transport rollers form a pass-line for the flat rolled material,        where at least one lower spray bar is arranged beneath the pass-line.        
A cooling line of this type is generally known.
In the prior art, so-called laminar cooling is often effected. In laminar cooling, the cooling section has at least one spray bar, which is arranged beneath the transport rollers. Welded into the spray bar and running parallel to the roller axes there is usually a row of small tubes, which project upwards in the direction of the rolled material. These small tubes are spaced apart, on the one hand looking in the direction of transport, from the transport rollers and also, on the other hand looking in the direction of the roller axes, from each other. The coolant which is applied from beneath onto the rolled material can therefore be drained away without problem.
Recently, so-called intensive cooling has become known. Intensive cooling is a new type of cooling method for cooling a rolled material during hot rolling, or immediately thereafter. It is used in order to adjust selectively the microstructure, and with it the mechanical properties, of the end product. In particular, so-called AHSS (=advanced high strength steels) call for ever more intensity of cooling and flexibility of cooling. These requirements are met by intensive cooling. For intensive cooling, the lower spray bars must be constructed differently than for laminar cooling. In particular, the lower spray bars must have larger dimensions. Furthermore, the lower spray bars must withstand the higher pressures which arise with intensive cooling.
In the prior art, a lower spray bar for intensive cooling is known. The known spray bar fills the entire space between directly neighboring transport rollers. This hinders the drainage of the coolant sprayed from below onto the flat rolled material. Consequently, a substantial excess quantity of coolant is required in order to achieve any particular cooling effect.
From DE 102 15 229 A1 a cooling section is known, for a flat rolled material, in which the cooling section has a structural frame in which a plurality of transport rollers is arranged one behind another in the direction of transport of the flat rolled material. In each case, transport rollers which are immediate neighbors looking in the direction of transport have a gap between them. Each of the transport rollers is mounted in the structural frame so that each roller can rotate about a roller axis, whereby the roller axes are oriented orthogonally to the direction of transport and horizontally, so that the transport rollers form a pass-line for the flat rolled material. Arranged underneath the pass-line is at least one lower spray bar which has a base block, arranged beneath the transport rollers, into which is fed a liquid coolant. The lower spray bar has a base body which tapers towards its upper side. On its upper side, the base body has bores, into which are set spray tubules, which are closed off in the upward direction by a nozzle. The spray tubules have a cross section which is as such constant.